[PATCH] Fix unnecessary xwidget_view creation

[Jaesup Kwak <veshboo@gmail.com>]

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Hi!

While I am trying out xwidget in master branch, I found many xwidget
views are made and kept in `xwidget-view-list' for one xwidget model
while I have only one xwidget buffer open.

I am attaching a patch for the problem and here is how to test.

Test procedure:

1. `xwidget-webkit-browse-url' to a web page

2. Resize emacs frame, scroll it up/down several times

3. C-x b to *scratch* and C-x 1

4. check with `(length xwidget-view-list)'

Expected output is 1
Actual output is > 1

Thanks,

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From cbd894121367cda2bd412bffec5412540fe6c7f9 Mon Sep 17 00:00:00 2001
From: Jaesup Kwak <veshboo@gmail.com>
Date: Mon, 6 Nov 2017 03:47:11 +0900
Subject: [PATCH] Fix unnecessary xwidget_view creations

* src/xwidget.c (x_draw_xwidget_glyph_string): Don't create new
  xwidget view if we have one already.

Copyright-paperwork-exempt: yes
---
 src/xwidget.c | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/src/xwidget.c b/src/xwidget.c
index a0c9e03477..fb776fb189 100644
--- a/src/xwidget.c
+++ b/src/xwidget.c
@@ -585,22 +585,20 @@ x_draw_xwidget_glyph_string (struct glyph_string *s)
      xwidget on screen.  Moving and clipping is done here.  Also view
      initialization.  */
   struct xwidget *xww = s->xwidget;
-  struct xwidget_view *xv;
+  struct xwidget_view *xv = xwidget_view_lookup (xww, s->w);
   int clip_right;
   int clip_bottom;
   int clip_top;
   int clip_left;
 
-  /* FIXME: The result of this call is discarded.
-     What if the lookup fails?  */
-  xwidget_view_lookup (xww, s->w);
-
   int x = s->x;
   int y = s->y + (s->height / 2) - (xww->height / 2);
 
   /* Do initialization here in the display loop because there is no
      other time to know things like window placement etc.  */
-  xv = xwidget_init_view (xww, s, x, y);
+  /* Do not create new one if we have found one to use. */
+  if (!xv)
+    xv = xwidget_init_view (xww, s, x, y);
 
   int text_area_x, text_area_y, text_area_width, text_area_height;
 
-- 
2.13.6 (Apple Git-96)